#define _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h>
void math(int* x,int* y)
{
   int c = *x;
   *x = *y;
   *y = c;
}
int main()
{
  int a = 10;
  int b = 20;
  printf("a=%d,b=%d\n",a,b);
  math(&a,&b);
  printf("a=%d,b=%d\n",a,b);
  return 0;
}